The invention relates to preparations, a component tape and a component tape reel for marking printed circuit boards with respective unique identification codes.
During manufacturing of printed circuit boards it is most often desired to be able to track and trace the manufactured circuit boards. For this reason, each manufactured circuit board may be provided with an identification code unique to the circuit board. Such is marking of circuit boards with unique identification codes can, for example, be made by ordinary stickers. In case optical readability of the code is desired, the sticker may include the code in the form of a bar code or some other readable code. In the prior art, circuit boards are often marked with identification codes by having the code laser marked or edged on the circuit board.
An example of an identification code that suitably can be used for marking circuit boards is disclosed by Priddy et al. in U.S. Pat. No. 5 484 999. This document described a machine readable, two-dimensional matrix representing a binary code. One such code is formed as a xe2x80x9cchecker boardxe2x80x9d symbol that represents information in the form of light and dark squares. This code is variable in size, format and density of information. The code allows a scanning computer to recognize, understand and act upon the encoded information regardless of the actual physical size or volume of data contained within the symbol representing the code.
JP, 06328275, discloses a method for improving the durability of codes marked on steel articles by oxidation or laser.
In all of the above described schemes for marking a circuit board, there is the problem of design space limit on the circuit board, i.e. the problem of finding a suitable, and big enough, space for the marking on the board. Another problem is that determination of such a space is separated from the board design process during which the board space utilization is optimized using a computer executed optimization program specifically designed for such a task. Thus, the existing solutions for marking circuit boards will require a certain amount of non-automated interaction with the circuit board manufacturing process, or possibly even with each single manufactured circuit board.
Another problem is that each circuit board manufacturer needs to adopt and implement its own process to be used for marking its manufactured circuit boards.
An object of the invention is to enable a more efficient, and a more cost effective, marking of printed circuit boards or of products including printed circuit boards.
Another object is to overcome at least one of the problems mentioned above with respect to marking of printed circuit boards.
According to a first aspect of the present invention, a method of making preparations for marking printed circuit boards with respect to unique identification codes includes the steps of printing unique identification codes on respective carriers, and packaging the carriers in such a way that the carriers are retrievable by an automated component mounting process for mounting the carriers on respective printed circuit boards. The identification codes may be codes which are optically readable by a machine. The identification codes may be two-dimensional matrices representing binary codes which are optically readable by a machine. The printing step may include printing the unique identification codes by way of laser marking of the carriers. The printing step may include printing the unique identification codes by way of punching of the carriers. The packaging step may include packaging the carriers on a component tape for surface mounted device (SMD) components. The carriers may be metallic carriers. The carriers may be carriers with a lower metallic part and an upper plastic part, the printing step including printing on the plastic part of the carriers.
According to a second aspect of the present invention, a method of making preparations for marking printed circuit boards with respective unique identification codes, includes the steps of printing unique, optically-readable identification codes on respective carriers, and packaging the carriers on a surface-mounted device (SMD) component tape for subsequent retrieval and mounting on respective printed circuit boards.
According to a third aspect of the present invention, a surface-mounted device (SMD) component tape with carriers for mounting on respective printed circuit boards is provided wherein each carrier is marked with an identification code which is unique for that carrier. The identification code of the SMD component tape may be a code which is optically readable by a machine. The identification code of the SMD component tape may be a two-dimensional matrix representing a binary code which is optically readable by a machine. Each carrier may be laser-marked with an identification code which is unique for that carrier. Each carrier may be punch-marked with an identification code which is unique for that carrier. The carriers may be packaged on the component tape for SMD components. The carriers may be metallic carriers. The carriers may be carriers with a lower metallic part and an upper plastic part, wherein it is the plastic part of each carrier that is marked with an identification code which is unique for that carrier.
According to a fourth aspect of the present invention, a surface-mounted device (SMD) component reel having a component carrier tape includes a tape with carriers for mounting on respective printed circuit boards wherein each carrier is marked with an identification code which is unique for that carrier.
According to the invention, carriers with respective unique identification codes printed thereon are packaged and provided in such way that the carriers can be mounted on respective circuit boards by an automated component mounting process. Thus, the invention enables a surface mount placement system to pick the carriers for placement on respective circuit boards, thereby marking the circuit boards with respective unique identification codes in a fully automated manner.
By providing the carriers in a component tape, or in a component tape on a component reel, the invention makes it possible for a surface mount placement system to use a standard tape feeder when picking the carriers and placing them on the circuit boards.
As the carriers, or the pick and place pads, have respective unique identification codes printed thereon, the process of marking a printed circuit board, or a product which includes a printed circuit board, is greatly simplified and made much more cost effective. As is understood such unique marking is desired in order to be able to track the product or circuit board during its manufacturing, its intermediate storage before shipment, as well as after its shipment to a customer.
As the invention enables the surface mount placement system to mark circuit board in accordance with a pick and place process normally used for mounting components, the marking of the circuit boards can be made in accordance with the chosen circuit board design rules. This makes it possible to take design space limit problems into account also for the marking process. Thus, the invention will enable a circuit board manufacturer not only to save board space, but also to improve the planning of the board space, both of these issues often being of great importance for a circuit board manufacturer in order to achieve efficiency and cost effectiveness when producing circuit boards.
Another advantage with the invention is that it eliminates the need for every circuit board manufacturer to implement its own process of marking the circuit boards. Instead, with the present invention the carrier carrying the circuit board identification codes may be produced at a single location and then shipped, in component tapes, to different circuit board manufacturers at different locations.
Advantageously, to enable an efficient way of tracking and tracing the marked circuit board, each identification code printed on a carrier represents an optically readable binary code. According to an embodiment of the invention, the identification code may be a two-dimensional matrix representing a binary code in accordance with that disclosed in the prior art.
The printing of the identification codes on the carriers can be performed in a variety of different ways. It may be printed on the carrier using any of the techniques presently used for directly marking the surface of a circuit board, i.e. by laser marking, edging, oxidation or punching.
The carriers may be metallic carriers or carriers with a lower metallic part that has a softer upper part provided thereon. Such softer part may be made of a plastic layer, but also other soft materials suitable for the printing method chosen may be used for this upper part. The advantage of providing the carrier with a soft, e.g. plastic, upper part is that the printing of the carrier can be made faster if the printing is performed on a soft part rather than on metal.